See instructions): The Children's Hospital of Philadelphia (CHOP) proposes to continue our NICHD-sponsored Institutional Ruth L. Kirschstein National Research Service Award (NRSA). Our goal is to increase the number and effectiveness of subspecialty pediatricians with a rigorous training in basic, translational and clinical research. We accomplish this by training outstandingpediatric fellows to become successful physician-scientists, addressing questions of fundamental importance to health and disease in children. Candidates for our program are enrolled in our subspecialty fellowship programs who are identified through national searches for the best and the brightest. Each candidate will identify a prospective mentor from a group of 40 mentors: 36 from CHOP (Pediatrics, Pathology, Surgery) and 4 from the University of Pennsylvania (Penn). These CHOP-T32-NRSA mentors were chosen by the following criteria: rigorous science in areas germaine to pediatrics, a record of successful mentoring and collaboration, a strong record of extramural funding, and programmatic balance. Trainee progress is reviewed twice a year by our Core Advisory Committee. Subspecialty trainees are supported for two years to conduct research as outlined in their formal proposals. Trainees in basic and translational research have access to a wide variety of outstanding mentors and educational opportunities, all supported by a wide array of clinical and laboratory research cores. Our T32-NRSA and the companion K12-CHRCDA grant have been highly successful in training physician-scientists who are capable of conducting independent research and who have consistently assumed academic positions. Five of the 11 have obtained advanced (Master's) degrees. This renewal of our CHOP-T32-NRSA will continue the tradition established for the first 5 years of this grant, taking advantage of the tremendous strengths of CHOP as an academic pediatric institution with an outstanding pool of subspecialty fellows, a large number of experienced mentors, and cutting edge research programs. CHOP and Penn provide a very comprehensive, well-supported and resource-intense environment, as well as a proven track record of training academic investigators in basic, translational and clinical research. Relevance: The training of physician-scientists in pediatric subspecialties is critical for advancing the understanding and treatment of childhood diseases, and for providing future leaders in academic pediatrics. RELEVANCE (Seeinstructions): Pediatric medicine's contribution to the health and welfare of future generations requires that physician- scientists continue to be trained in highly academic environments. CHOP is such a place with its long history of achievement in all areas of academic pediatrics. This application proposes to enhance previous training efforts at the postgraduate level, in order to provide a new generation of pediatric physician-scientists with the skills and professional foundation necessary to lead future initiatives in basic and translational research.